Tailpiece protector



Feb. 26, 1963 F. J. RUSSELL TAILPIECE PROTECTOR 2 Sheets-Sheet 1 Filed April 25, 1960 EMIm JNVENTOR. fe@ d; 19055511.

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Feb. 26, 1963 J. RUSSELL 3,078,706

TAILPIECE PROTECTORv Filed April 25, 1960 ,4 LL? l 60 2 Sheets-Sheet 2 l? 27' 25a 30. ll-\ `H n 29 my A JNVENToR. rf. RUSSELL United States Patent O M 3,078,706 TAILPIECE PROTECTOR Fred J. Russell, 3800 Don Felipe Drive, Los Angeles, Calif. Filed Apr. 25, 1960, Ser. No. 24,378 Claims. (Cl. 70-419) The invention relates to door locks and particularly locks which have key-operated unlocking mechanisms. More especially the invention has refeernce to a device for preventing locks of the kind made reference to from being unlocked by unauthorized means.

When such key-operated locks are built, there are certain qualifications which need inherently to be built into them. Some of these include construction which will 3,078,706 Patented Feb. 26, 1963 2. contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the laccompanying drawings.

In the drawings:

FIGURE l is a longitudinal sectional view of one form of the device showing a key in normal unlocking position.

permit the key-operated mechanism to be removed or taken apart when needed for servicing or perhaps rekeying. Obviously also the structural parts of the lock must 4be such that they can be manufactured by use of the usual -tools and then put together properly in order that they may work effectively. Ordinarily a tailpiece or spindle is attached to the cylinder plug in which the key ordinarily is inserted so that when the cylinder plug is rotated by en'iployment of a proper key, the tailpiece will be rotated for the purpose of unlocking the lock.

FIGURE 2 is a Across-sectional view on the line 2-,2 of FIGURE 1.

FIGURE 3 is a fragmentary longitudinal sectional view of the device of FIGURE 1 with the key removed.

FIGURE 4 is a cross-sectional view taken on the line 4-4 of FIGURE 3.

FIGURE 5 is a longitudinal sectional view at right angles to the view of FIGURE 3 taken on the line 5 5 of FIGURE 3.

FIGURE 6 is a fragmentary longitudinal sectional view of `a modified lform of the device.

FIGURE 7 is a cross-sectional View taken on the line 7-7 of FIGURE 6.

FIGURE 8 is a fragmentary longitudinal sectional view of still a third form of thetdevice.

"Despite the lcare with which these devices have been .v

constructed heretofore, it has been possible by persons ladroit at the handling of locks to insert a specially constructed spring metal shim through the keyway, and by having the shim of a proper type of material it has been possible to work it from the keyway in an offset direction into the area where the tailpiece joins the cylinder plug, .this operation being folowed by the exertion of endwise pressure on the shim simultaneously with rotation of it, thereby to disengage the tailpiece from the cylinder plug so that it can be rotated by the shim and the lock accordingly unlocked or to rotate the tailpiece to extent of a rotation permitted by a lost motion connection between the tailpiece and cylinder plug. In either case, the tailpiece is rotated to unlock the lock in spite of the fact that cylinder plug does not rotate.

To makel such means of inadvertently unlocking the -lock ineffective, it is an object of the invention to provide a new and improved construction for the interior of the cylinder plug at the area of junction with the tailpiece which is capable of barring or blocking admission of an unauthorized tool through the keyway to a point where it 4is capable of manipulating the tailpiece to unlock the lock.v

Another object of the invention is to provide a new and improved tailpiece protector in the form of a block which bars the way between the keyway and the tailpiece yin such fashion that a shim of the kind depended upon for picking locks cannot span the protector suliciently effectively to grip the tailpiece on the other side of the lprotector in a fashion necessary to unseat it and/ or rotate it in order to release the lock. v

Still another object of the invention is to provide a new and improved tailpiece protector which may constitute either a separate blocker or a blocking device in the recess which receives the tailpiece or actually an extension of the tailpiece itself, the blocker or the extension, whichever may be used, being rounded on the exterior to inhibit being gripped for rotation by an unauthorized tool and further being so constructed that a tool capable of being inserted in the keyway cannot be worked around the blocker suiiciently to engage the tailpiece on the other side in a manner permitting unautho-rized unlocking of the lock. Y

With these and other objects in view, the invention consists in the construction, arrangement and combination of Ithe various parts of the device, whereby the objects FIGURE 9 is a cross-sectional view taken on the line 9 9 of FIGURE 8.

FIGURE 10 is a perspective view of the tailpiece with tailpiece protector embodied therein of t-he type shown' in FIGURES 8 and 9.

In an embodiment of the invention chosen for the purpose of illustration there is shown what is substantially a conventional pin tumbler lock in which the tailpiece protective feature is incorporated. This pin tumbler lock comprises essentially a cylinder barrel 10 within which rotates a cylinder plug 11 operated by a key 12. A pin t-umbler ilange 13 forms part of the cylinder barrel and contains the usual pin tumbler bores 14 which Iare adapted to align axially with. matching pin tumbler bores 15 in the cylinder plug. Pin tumblers 16 under pressure of springs 17 urge the pin tumblers 16 downwardly, as viewed in FIGURE l, against matching pin tumblers 18 in the pin tumbler bores 15, the pin tumblers 18 being moved thereby through action of the springs 17 downwardly to positions where they bottom against a longitudinal -rib 19 in a keyway 20. In this adjustment the lock is in locked position inasmuch as the sylinder plug 11 cannot be rotated because of partial projection of the pin tumblers 16 from the bores 14 into the bores 15, Following conventional practice, when the key is inserted appropriate cut-outs `and projections match the pin tumblers 18 so that when the key is in place, the line of separation between the pin tumblers 16 and the pin tumblers 18 Will fall on the circumference of the cylinder plug and permit the plug to rotate in the cylinder barrel 10.

In order to transmit rotation of the cylinder plug 11 to the conventional key-operated unlocking mechanism (not shown), a non-circular spindle or tailpiece is employed here shown as a square tailpiece 25. For mounting the tailpiece there is provided a cap 26 in threaded engagement with a tail stock 27 and a portion of the cylinder` plug sufficient to bring the tailpiece snugly into engagement with a plate 28 which bears yagainst the cylinder barrel 10. In the cap is a compression spring 2.9 bearing at one end against the bottom of the cap and at the other end against a yoke 30. The yoke has ends 31 and 32 which engage respectively in a slot 33 of the tail stock which is in fact an extension of the cylinder plug. The square tailpiece is non-rotatably contained within a square vhole 34 in the cap and also non-rotatably contained within a flattened end 25a which holds the tailpiece against end-- wise removal from the yoke.

When these parts are assembled yand disassembled, it is necessary only to withdraw the yoke 30 from engagement with the slot 33` whereupon the cap 26 can be un'- screwed lfrom the cylinder plug for disassembly. Contrarily during ythis disengagement the cap may also be screwed onto the cylinder plug to assemble the parts, until teh yoke is in a proper degree of rotation to permit the ends 31 to be projected into the slot 33.

When a lock of this type is sought to be picked .by unauthorized persons employing an` unauthorized tool of some description other than the proper key, the object is to disengage the tailpiece from its non-rotatable connection to the cylinder plug and thereafter rotate the tailpiece in order to unlock the locking mechanism. This is ordinarily accomplished by employment of a spring steel shim, very thin, and relatively narrow, and which is provided with an open end wrench recess. The lock picking procedure involves inserting thespring steel shim through that portion of the keyway removed from the pin tumblers 18 and forcing the inner end suicient to have it pass from the keyway 20 intoran opening 36 in the tail stock communicating with the slot 33, suicient pressure being exerted upon the spring steel shim to then pushagainst the flattened end 25a and the tailpiece far enough to diss engage the ends 31 of the yoke 30 from the slot 33. Thereafter, by virtue of the fact that there is a recess at the end of the shim receptive of the llattened end or even the at sides of the tailpiece 25, the tailpiece can be rotated by rotating the shim. At the same time the cap 26 is unscrewed slightly from the cylinder plug. In this fashion the locking mechanism can be unlocked without disturbing the pin tumbler relationship which otherwise prevents unlocking except when an authorized key rotates the cylinder plug.

It is to prevent this inadvertent picking of the lock that there is providedin a lockof the type described a separate cylindrical blocker 40. The blocker lies within the opening 36 and extends from the bottom of the opening to a position just clearing the flattened end 25a. Posif tioned as described, it becomes extremely difticult to force the usual lockV picking spring steel shim into the opening 36 and against the tailpiece with sufficient force to disengage the tailpiece from the cylinder plug. To further assure that the lockrcannot be thus inadvertently unlocked, the cylindrical exterior of the blocker is such that it cannot be grasped by a recessed or open end wrench etect at the inner end of the shim. The blocker, moreover, is long enough to prohibit employment of legs forming an open end wrench on the shim from spanning the blocker and grasping the tailpiece. Hence even if the tailpiece is released from non-rotatab1e engagement with the cylinder plug, it cannot be rotated by the shim and the lock cannot thus be picked.

In the form of device shown in FIGURES 6 and 7 all of the conventional parts of the pin tumbler lock are the same as has been described in connection with FIGURES 3 through 5, inclusive, and are correspondingly numbered. In this form a blocker 41 has substantially the same cross-sectional shape as the key 12, the shape of which is clearly shown in FIGURE 7. The blocker lies within the inner end of the keyway 20 and substantially Iills the keyway. As shown the blocker has channels 42 and 43 which receive respectively the rib 19 and a second rib 44. Inasmuch as the blocker 41 lies in the keyway, it cannot be rotated unless the cylinder plug is rotated and this is prevented by the conventional pin tumblers when the lock is locked. Moreover, inasmuch as the blocker etectively fills the keyway, it substantially bars a spring steel shim from being forced through the keyway into engagement with the attened end 25a of the tailpiece 25. However, even if this last described act could be accomplished by a lock picking spring steel shim which obviously must be at enough to pass through the lower portion of the keyway 2t), the shim could still not be rotated in order to rotate the tailpiece because rotation of the shim would be blocked by presence of the blocker 41 in the keyway. Hence, the blocker effectively prevents unlocking of the lock through the agency of the tailpiece 2S by unauthorized means.

In the third form of the device there is provided a tailpiece 25' which is equipped with a cylindrical extension 5t) in place of the flattened endZSa. The cylindrical extension is the same material as the tailpiece Z5 but shaped so as to present a cylindrical exterior which cannot be grasped by an open end wrench-like configuration on the lock picking shim. An annular ilange 51 at the junction of the cylindrical extension with the tailpiece 25 bears against the yoke 30 so that by pulling on the tailpiece 25' the yoke and its ends 31 can be disengaged from the slot 33. In this form of device the cylindrical extension passes into the opening 36 and is free to rotate in the opening when the yoke 30 and its ends are disengaged. Contrarily, when in engagement as shown in FIGURES 8 and 9, the cylindrical extension blocksaccessfto the yoke 30 by means of the passing of a spring steel lock picking shim through the keyway in the manner previously described. Not only does the cylindrical extension bar effectively the passage of the `shim of suicient proportions but by presenting a cylindrical exterior avoids presenting any flat areas to the shim which could be grasped in order to inadvertently rotate the tailpiece.

There has accordingly been disclosed an extremely simple and effective agency for preventing lock tail pieces from being rotated by unauthorized means. The arrangement avoids necessity for making any appreciable changes or alterations in the structure and accordingly is one notoriously inexpensive to incorporate in such locks and which at the same time is highly elective.

While the invention has herein been shown and described inwhat is conceivedrto be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claimsso as to embrace any and all equivalent devices.

Having described the invention, what is claimed as new in support of Letters Patent is:-

1. In a key-operated unlocking mechanism including a cylinder plug therein, a longitudinally extending keyway having the full width thereof extending continuously throughout the full length of the plug, a tailpiece having an axially shiftable and limited rotatable engagement with the plug, said plug having a space at the inner end of the keyway and in communication with said keyway, a blocker between the end of said cylinder plug andthe end of said tailpiece, said blocker comprising a piece of material separate from said plug and removablly positioned in said space at the inner end of the keyway and being in axial alignment with said tailpiece and said keyway, whereby to prevent access to the tailpiece through the keyway by an unauthorized instrument and to inhibit releasing movement of said tailpiece.

2. In a key-operated unlocking mechanism including a cylinder plug therein, a longitudinally extending keyway through the plug, a tailpiece having a limited rotatable engagement with the plug, a blocker between the end of said cylinder plug and the end of said tailpiece, said blocker being in axial alignment with said tailpiece and said key.- way, whereby to prevent access to the tailpiece through the keyway by an unauthorized instrument and to inhibit releasing movement of said tailpiece, said blocker cornprising a separate element located in a recess at the innermost end of the cylinder plug.

3. In a key-operated unlocking mechanism including a cylinder plug therein, a longitudinally extending keyway through the plug, a tailpiece having a limited rotatable engagement with the plug, a blocker between the end of said cylinder plug and the end of said tailpiece, said blocker being in axial alignment with said tailpiece and said keyway, whereby to prevent access to the tailpiece through the keyway by an unauthorized instrument and to inhibit releasing movement of said tailpiece, said blocker comprising a separate element corresponding approximately in cross-sectional shape to the cross-sectional shape of the keyway.

4. In a key-operated unlocking mechanism including a cylinder plug therein, a longitudinally extending keyway through the plug extending continuously from end to end thereof, a tailpiece having a limited rotatable engagement with the plug, a blocker between the end of said cylinder plug and the end of said tailpiece, said blocker being in axial alignment with said tailpiece and said keyway, whereby to prevent access to the tailpiece through the keyway by an unauthorized instrument and to inhibit releasing movement of said tailpiece, said blocker comprising a cylindrical extension at the inner end of the tailpiece.

5. In a key-operated unlocking mechanism including a cylinder plug therein, a longitudinally extending keyway through the plug extending continuously from end to end thereof, said plug having an opening extending from the inside end of the keyway inwardly of the plug and at the axis of rotation of said plug, said opening being Wider than said keyway, a tailpiece having a limited rotatable engagement with the plug, a blocker between the end of said cylinder plug and the end of said tailpiece, said blocker being in axial alignment with said tailpiece and said keyway, whereby to prevent access to the tailpiece through the keyway by an unauthorized instrument and to inhibit releasing movement of said tailpiece, said blocker comprising a cylindrical extension at the inner end of the tailpiece greater in width than the width of said keyway and substantially lling the Width of said opening.

References Cited in the le of this patent UNITED STATES PATENTS 1,556,242 Murphy Oct. 6, 1925 2,199,165 Smith Apr. 30, 1940 2,803,959 Schlage Aug. 27, 1957 

1. IN A KEY-OPERATED UNLOCKING MECHANISM INCLUDING A CYLINDER PLUG THEREIN, A LONGITUDINALLY EXTENDING KEYWAY HAVING THE FULL WIDTH THEREOF EXTENDING CONTINUOUSLY THROUGHOUT THE FULL LENGTH OF THE PLUG, A TAILPIECE HAVING AN AXIALLY SHIFTABLE AND LIMITED ROTATABLE ENGAGEMENT WITH THE PLUG, SAID PLUG HAVING A SPACE AT THE INNER END OF THE KEYWAY AND IN COMMUNICATION WITH SAID KEYWAY, A BLOCKER BETWEEN THE END OF SAID CYLINDER PLUG AND THE END OF SAID TAILPIECE, SAID BLOCKER COMPRISING A PIECE OF MATERIAL SEPARATE FROM SAID PLUG AND REMOVABLY POSITIONED IN SAID SPACE AT THE INNER END OF THE KEYWAY AND BEING IN AXIAL ALIGNMENT WITH SAID TAILPIECE AND SAID KEYWAY, WHEREBY TO PREVENT ACCESS TO THE TAILPIECE THROUGH THE KEYWAY BY AN UNAUTHORIZED INSTRUMENT AND TO INHIBIT RELEASING MOVEMENT OF SAID TAILPIECE. 